


21st Birthday Rebellion

by intothecest



Category: Gravity Falls
Genre: Adult Dipper Pines and Mabel Pines, Aged-Up Character(s), Birthday, Brother/Sister Incest, Dialogue-Only, Drabble, Drunken Confessions, Drunken Shenanigans, F/M, No Smut, Post-Gravity Falls, Twincest, Unresolved Sexual Tension, pinecest - Freeform
Language: English
Status: Completed
Published: 2020-08-31
Updated: 2020-08-31
Packaged: 2021-03-07 02:00:11
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 891
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26219011
Author URL: https://archiveofourown.org/users/intothecest/pseuds/intothecest
Summary: It's Mabel and Dipper's 21st birthday, and Mabel's a little disappointed.
Relationships: Dipper Pines & Mabel Pines, Dipper Pines/Mabel Pines
Comments: 2
Kudos: 18





	21st Birthday Rebellion

**Author's Note:**

> So August 31st is canonically the twins birthday, and if we assume that their 13th birthday took place in 2012 when the series debuted (even though it was three seasons it all took place over a single summer), that this year, 2020, would be their 21st birthday. So I was inspired to write a quick fic about it. Because of the time pressure I couldn't really plan it out as much as I normally do so I pretty much just went with my first impulses.

"Hey Dip-dip... the designated driver took everyone else home, so I guess it's just us. You want another drink?"

"I don't know, Mabel... I've had an awful lot. It might be time to call it..."

"No."

"Come on, you know the drill... this was the best..."

"I don't wanna..."

"...birthday..."

"Dipper, no..."

"Did you not have fun?"

"No, I did. It's just... I don't know, I don't want to say our end-of-birthday ritual. Maybe I just don't want to say 'good night' yet. This one's different. It's the end. The end of our teenage rebelliousness."

"That was _last_ year, Mabel. We haven't been teenagers for a whole year."

"I know, but... twenty's like _basically_ teenager. Like how you always used to say that technically new centuries start on the the zero-one because there was no year zero. Twenty-one is officially adult by every measure. I mean look at this bottle. I bought this with my own ID today. Just walked right in there and they gave it to me. No sneaking around with a fake, hoping he didn't call us on it and get us in trouble."

"Not that he ever would. It's a college town. And we never did _much_ underage drinking anyway."

"Yeah, but when we _did_ , it was _special_ , because we would have gotten in trouble... and now we don't even have that, because we're twenty-one. Boring adults. And time's still just zipping by. Remember that summer we spent in Gravity Falls? That felt like it took _three years_ to get through, and I still thought it went by too fast. But I was an idiot... this last year, _zoom_. We've been so busy in school we didn't even get a chance to enjoy our last year before we're adults. We used to rebel against the system. Now we officially are part of it."

"... a lot of places make you wait until you're 25 to rent a car. We could try to illicitly rent a car. I mean, not tonight--when we're sobered up."

"It's not the same, Dipper. And besides, that wouldn't be birthday rebellion. It would be a _post-_ birthday rebellion."

"And it won't be our only chance for it, either. There's still protests and counterculture and plenty of ways to fight the system. The Mabel Pines I know isn't going to surrender to boring just because she hit an arbitrary number. And if you want to do something crazy and rebellious before we finish off the night, I'm game, but you better think of something fast, I need to get to bed."

"Oh my god, That's it, Dipper!"

"What."

"Bed! We should totally _fuck_."

"Mabel!" 

"Sorry, was that too loud? We should totally _fuuuuuuuuuuuuuuuck_."

"That was the same volume! You just said it slower! And it didn't make any more sense this time! Clearly you're drunk out of your mind right now."

"No, come on Dipper... it's so _taboo_! We'd get in so much trouble, we'd have to keep it totally secret! A perfect way to rebelliously celebrate adulthood."

"Mabel... this is the alcohol talking, we're not committing... like, the ultimate sin just so you can convince yourself you've still got a spark of rebellion in you."

"Why not? I've always wanted it, you've always wanted it, what's the harm?"

"It's... wait, you've always wanted it?"

"I mean, yeah, it's like sex with someone who totally understands you. I just figured _you_ didn't want to take the risk of getting in trouble. But tonight, we're both drunk enough to go for it!"

"I, uh, don't think I'm _that_ drunk, Mabel..."

"You sure you don't want another drink then, bro? Then we could totally _fuuuuuuuuuuuuck_."

"Stop saying that! And stop saying it _like_ that! We are not having drunk incest sex Mabel."

"Spoil-sport. There goes my last shot at birthday rebellion. So much for our ' _best birthday ever_ ' tradition too *sigh* Night Dipper."

"I mean... maybe we could _agree_ to have sex."

"What? You mean it? We're actually going to _fu..._ I mean, _make the multi-bear with only two heads_?"

"That's... that's _not_ a better way to say it, Mabel. And no, we're _not_ going to have sex tonight."

"But you just said..."

"We're both way too drunk to have sex."

"I mean I think I still know _how_ , Dip, don't you?"

"We're drunk, and consent gets dubious. But we could agree, _in principle_ , to have sex, at some time we're both sober, if we both still want to. Since we're agreeing, tonight, to something taboo, it's still an act of rebellion."

"Are you sure this isn't just a way to say no without hurting my feelings? Since when we're sober you won't want to take the risk?"

"I don't know, but if I don't, the fact that I'm even _suggesting_ shows I'm too drunk right now. Tomorrow... well, if we want to."

"But we're agreeing, tonight."

"Right. Shake on it?"

"You've got a deal, bro-bro. One thing though."

*mwah*

"Mabel..."

"Just figured I'd seal the agreement with a kiss. That way if we chicken out, at least I have a good birthday memory. So we going to say it now, or what?"

"I'm ready if you are."

"This was the best birthday ever!"

"This was the best birthday ever!"

"Night Dip."

"Night Mabel."

"See you tomorrow. Hope it's going to be a year to remember."


End file.
